For detecting the presence of such microorganism in food as Escherichia coli, Staphylococcus aureus, Vibrio or the like, that causes food poisoning, a method that has been widely practicing involves adding a test sample in a fluid culture medium with a color-turning indicator mixed in it. The determination of whether or not a test sample is contaminated with microorganisms is accomplished by observing the indicated color response of a mixture after a mixture is incubated at suitable temperature for certain period of time.
However, with the commonly used technique, it requires longer time to detect the presence of microorganisms with a color response since the choice of indicator is constrained to avoid adverse effect on the growth of microorganisms when an indicator is mixed with a liquid culture medium. It is also known that some indicators interfere the growth of microorganisms and in some cases a culture medium degrades the performance of an indicator when they are mixed together. Furthermore, by observing a color change of a mixture, the determination of microbial detection becomes harder and a wrong result might be led if a color of a test sample itself is dark or deep.
The objective of the present invention is to provide a simple, efficient, fast and reliable microbial detection by;    (a) a method for detecting the presence of microorganisms,    (b) a method for identifying the quantities of microorganisms,    (c) self-contained microbial detection tools,    (d) a microbial detection system, and    (e) a microbial growth time measuring system, without an indicator interfering the growth of microorganisms, without a culture medium degrading the performance of a indicator and without a color of a test sample adversely effecting the process of microbial detection, while providing a solution to the commonly used technique to overcome its drawbacks.